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United States Department of Agriculture

Agricultural Research Service


item Fatemi, Peyman
item Knabel, Stephen
item La Borde, Luke
item Annous, Bassam
item Sapers, Gerald

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/9/2006
Publication Date: 8/12/2006
Citation: Fatemi, P., Knabel, S.J., La Borde, L.F., Annous, B.A., Sapers, G.M. 2006. Factors affecting attachment of escherichia coli o157:h7 to apple tissues. Program and Abstract Book of 93rd International Association for Food Protection Annual Meeting. 2006. T7-01. Page 91.

Interpretive Summary:

Technical Abstract: Attachment of Escherichia coli O157:H7 and fluorescent microspheres to the stem, calyx sepals, russet and discontinuities on the skin of Golden Delicious apples was investigated. Attachment of the E. coli cells to the stems resulted in their removal from the inoculum solution over time where the cells were found within crevices spanning the length of the stem. Treatment of the stems with 5 percent trisodium phosphate, following immersion in inoculum solution for 30 seconds, resulted in only a 1-log reduction. Concentration of E. coli cells that attached to stems following immersion in inoculum were significantly higher than cells attached to stems that were pre-hydrated in sterile water prior to inoculation (p < 0.05). SEM imaging showed preferential attachment of E. coli to what appeared to be mold mycelia on the calyx sepals. Attachment to the russets was often observed within the cork cells. Cells were also found within discontinuities on the skin, especially at cell junctions. Confocal Scanning Laser Microscope imaging showed that regardless of their surface charge, hydrophobic microspheres attached more regularly than hydrophilic ones to various apple surfaces. Attachment of hydrophobic/negatively charged microspheres to similar surfaces suggests that attachment of E. coli to these regions is at least partially governed by hydrophobic interactions. Understanding bacterial interactions with produce surfaces may aid development of more effective methods to improve the safety of produce.

Last Modified: 10/19/2017
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